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April 26,1927. 1 1,625,874

F. W. SHUELL GAS VALVE Filed Feb. 4, 1924 Patented Apr. 26, 1927.

fU'N-flreb stares rnANK W., srijUELn, or DETROIT, MICHIGAN, 'iissiononfro Evian, rior 4iinnfrnia CM- PANY, or DETROIT, MICHIGAN, n oonronATroN or MICHIGAN.

GAS VALVE.

Application led February 4, 1924. Serial No. 690,614.

The invention relates to valves more particularly designed for the control of fuel gas to burners in automatic Water heaters, und the invention consists in the peculiar construction and arrangement of the thermostatically controlled and pilot valves, as hereinafter set forth.

In the drawings:

Figure l is a sectional elevation through a portion of a Water heater to which my improved valve is applied;

Figure 2 is an elevation partly in section at right angles to Figure l.

In the construction of automatic gas water heaters the fuel supply to the burner is controlled by a thermostatically operated valve, the thermostat being so arranged as to be exposed to the incoming cold water. The valve is also constructed and adjusted so that when the latter is exposed to the cold Water, the valve will be opened to the maximum and will gradually close as the Water in contact With the thermostat becomes heated. It is, however, necessary to maintain a pilot light for the burner and with certain constructions this light is obtained by merely reducing the flame in the burner itself. This requires very accurate control of the gas supply as a slight reduction might extinguish the flame While an over-supply Would cause overheating and cut down on efciency.

One of the features of the present invention is a valve construction permit-ting of accurate adjustment to suit conditions, such as pressure and quality of the gas, and to secure both certainty and eiiiciency in operation this consists in the combination with the thermostatically operated valve of a calibrated by-pass for supplying the pilot light.

In detail, A is the Water tank, B the sur` rounding jacket, C a gas burner in a chain ber in the jacket beloiv the tank, D the gas supply conduit, E the controlling valve, F the thermostat, and G the Water inlet to the tank surrounding the thermostat. Preferably the thermostat employed consists in a tube II projecting laterally into the tank and connected by a nipple I to the controlling valve E. Within the tube II is a rod J which is formed of material having a different coeflicient of expansion from that of the tube, such for instance as a carbon rod, the tube being formed of metal. The outer end of the rod J is connected to a longitudinally adjustable stem K, which is adapted to press against a disk valve L to displace the same from its seat, a spring M yieldably pressing said valve towards its seat. The arrangement is such that the contraction of the tube I-I when exposed to the cold Water, Will, through the medium of the rod J, force the valve L from its seat, While the heating of said tube Will expand the same and permit the spring M to completely seat the valve. l/Vith such a construction it would be difficult and practically impossible to supply the fuel for the pilot light through the main valve. This is for the reason; first, that a very slight separa tion of the valve from its seat would be required to limit the supply of gas for the pilot, and; second, if it Were possible to secure such an adjustment, a very slight obstruction might cut ofiz the supply. I have therefore provided a by-pass around the valve L and as shown this is placed in a byepass conduit N. In this conduit is a fitting O containing a removable calibrated plug, preferably in the form of a plug cock, which may be used for cutting` off the supply when the apparatus is not in operation. 'Ihe plug O is drilled to form a round aperture P suitably calibrated, and this, While accurately limiting the supply of gas, will be of sufficient size to prevent clogging.

In use, when the apparatus is installed, the plug O is selected with reference to the pressure and quality of gas. Thus if the pressure is low or the quality poor` thel aperature l) may be enlarged; or, if the pressure is high or quality is rich, a plug with a smaller aperture may be selected. In this Way the supply to the pilot light is reduced to the minimum and yet with perfect safety, as there is no danger of failure of supply Which Would extinguish the light. The construction also avoids the necessity of delicate adjustment of the thermostatically controlled valve, as this valve may be permitted to fully seat when the Water in the tank surrounding the thermostat is of the required temperature.

Wvhat I claim as my invention is:

The combination With a gas burner, a

llo

lOl)

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extend axially of said conduit, said opening being calibrated to limit the amount of gas passinoA therethrough to `that necessary 10 :t'or supplying the pilot light for the burner.

In testimony whereof I allix my signature.

FRANK W, SHUELL. 

